#define _CRT_SECURE_NO_WARNINGS 1
class Solution {
public:
    int dx[4] = { 0, 0, 1, -1 };
    int dy[4] = { 1, -1, 0, 0 };
    bool vis[1010][1010] = { false };
    int rotApple(vector<vector<int>>& grid)
    {
        int m = grid.size(), n = grid[0].size();
        queue<pair<int, int>> q;
        for (int i = 0; i < m; i++)
            for (int j = 0; j < n; j++)
                if (grid[i][j] == 2)
                    q.push({ i, j });
        int minute = 0;
        while (q.size())
        {
            minute++;
            int sz = q.size();
            while (sz--)
            {
                auto [a, b] = q.front();
                vis[a][b] = true;
                for (int k = 0; k < 4; k++)
                {
                    int x = a + dx[k], y = b + dy[k];
                    if (x >= 0 && x < m && y >= 0 && y < n && grid[x][y] == 1 && !vis[x][y])
                    {
                        vis[x][y] = true;
                        q.push({ x,y });
                    }
                }
                q.pop();
            }
        }
        for (int i = 0; i < m; i++)
            for (int j = 0; j < n; j++)
                if (grid[i][j] == 1 && !vis[i][j])
                    return -1;
        return minute - 1;
    }
};